Replaceable facing and pins therefor



G. E. COX. REPLACEABLE FACING AND PINS THEREFOR.

APPLICATION FILED SEPT. 8,1921- Patented Nov. 15, 1921 Greo. E. OX

A SWO .PATENT QFFIQE.

GEORGE E. COX, 0F

WILMENGTON,

DELAWARE.

.REPLACEABLE FACING AND FEES THEREFGB.

135E168 2,. Specification of Application filed September To all 201 mm.may conccm Be it known that l, GEORGE E. Cox, a citizen of the UnitedStates, residing at .l ilmington, in the county of New Castle and Stateof Delaware, have invented certain new and useful improvements inReplaceable Facings and Pins Therefor; and I do hereby declare thefollowing to be a full, clear, and exact description of the same,reference being had to the accompanying drawings, forming part of thisspecification.

This invention relates to dental facings in tended for bridge W Fla, andhas for its objeot the provision of a system that will provide asuperior article at a less cost than the present facing with permanentlyattached pins.

A further object of the present invention is the provision of areplaceable facing that may be protected with a gold tip, this beingimpossible with the popular oteeles interchangeable teeth. A furtherobject of the present invention is the provision of a facing that can bemade more convenient for the dentist than the present-day facing in thatthe tip of the facing here described may be ground by the maker so thatthe facing-s will be interchangeable without further grinding by thedentist. A still further but important object of the present inventionrelates to the pins per se, these pins being characterized by theprovision of a central collar intended to abut against the porcelainfacing on one side and against the 22-karat gold backing on the otherside.

In crown and bridge work the dental facings which are almost invariablyof porcelain very often crack when the metal is being soldered, andsince these backings have the pins inserted in them permanently theyconsequently cannot be removed when they crack. The present facing maybe removed while the bridge work is being soldered and it also can bereplaced if broken, while in the mouth, or it may be changed if theshade of the tooth does not match properly or is un satisfactory for anyreason whatever to the patient.

In the present system it is contemplated to use porcelain facings havingtwo relatively deep indentations or holes with preferably roughenedinterior walls and to cement in these holes a pair of connected dentalpins each having a plurality of cement receiving grooves so as to form apermanent attachment to the facing. The pins are pointed, as

Patented Nov. 15, 192i.

Letters Patent.

8, 1921. Serial No. 499,167.

is quite customary, in order to pierce the soft gold backing. It willreadily be understood by those skilled in the art that the pins are notpermanently cemented to the facings until after the bridge is otherwisecompleted.

In order to secure interchangeability of the teeth i prefer to have thefacings ground at the tip as shown in the drawing, but do not wish myinvention limited (except by the claims hereinafter) to a ground tipfacing, since teeth as usually furnished are not now ground and in viewof the necessity for changing the molds it might be that somemanufacturers would not care to grind the tips, but would desire to usethe present invention. If the tips are so ground at the factory it willobviate further grinding by the dentist at his oflice.

In toe drawings,-

Figure l is a vertical section through a facing embodying the invention.

ig. 2 is a rear elcvatiton of the facing i the pins and backing inplace.

' 3 is a view of the dental pins.

g. i is a section through a part of the bric ge with the facing,backing, and dental pins all in place.

The facing 10 is of quite ordinary shape, having a. bevel top 11 and aplane rear face 12 with the usual exposed surface 14: shaped to resemblea natural tooth. T prefer to grind away the tip as at 15 so as toprotect the facing by the provision of a contact edge 16 of gold. A.plurality of indentations or holes 1'? and 18 are provided, the upper'hole 1'? preferably being slightly deeper than the lower hole 18 butboth being preferably of the same diameter and both preferably havingroughened walls to facilitate the permanent connection by cement withthe dental pins.

The backing 19 is preferably of 36-gage gold plate and is cut by thedentist from sheet material thus greatly reducing the comparative cost.

The pins 20 and 21 are quite similar generally, but the pin 20 isslightly longer than the pin 21 since it fits in the upper and deeperhole 17 in the facing. Each pin has a pointed tip 22 and a pair ofannular flanges or heads, the outer head being numbered 23, and theintermediate head being numbered 2%. The pins 20 and 21 lie parallel andare connected together by a common collar 25 somewhat in the shape of adumb bell, the ends 26 being circular as.

model.

4 similar cement receiving grooves 29 with the outer heads 23.

Expensive machine-made backings are required to be used with other typesof removable and replaceable facings and the dentists are compelled tocarry in stock a comparatively large assortment of such backings to meetthe requirements for different size teeth, these, backings costing fromseventy cents to a dollar or more. If the dentist has only largebackings and requires a small one he must waste an appreciable amount ofmoney since a dollar backing contains only about thirty-live'cents worthof gold. In the present system there is practically no loss, for theQQ-karat 36- gage gold plate furnished dentists does DOT, cost much inexcess of its actual value so the dentist may cut his own backings as heneeds them.

The operation of applying the pins and facings is as follows: hen abridge is being made the work is usually mounted on a plaster model andthe facings or teeth, such as 10, are first fitted in place and held forobservation with beeswax. After the dentist is perfectly satisfied withhis selection as to shape, color, etc, he fits the chosen teeth orfacings to what is represented on the plaster model as gum tissueandafter carefully removing the facings one by one he inserts the pins20 and 21 as a unit in the holes 17 and 18 and burnishes the goldbacking 19 to the facing in the well known way and then returns thetooth facing to the If the tooth is a front one it is now ready to havethe gold melted to the backing, but if the tooth is a back o-ne thebiting surface or cusps 30 are swaged out of gold plate. I find ithighly advantageous to let the gold cusps 80 lap over the gold backing19 at 16 which allows the gold,

when melted, to permanently unite the limited except as set forth in theclaims. I

wish to use pins of equal length for example, and I wish to knurl orotherwise roughen the ends intended for insertion in the facing,although I much prefer the formation shown with its two annular cementreceiving grooves 28 and 29.

What I claim is:

i. In combination, a facing having two pin receiving holes, and a pairof pointed pins having a common central connecting collar, said pinsfitting in the holes in said facing. V

2. A pair of dental pins connected together for simultaneous insertionin a facing each of said pins being pointed at one side of theirconnection and roughened on the other side thereof. 7

3. A pointed dental pin characterized by the provision of a plurality ofannular flanges adapted to be received Within a facing and a collar oflarger diameter and adapted to abut the inner face of said facing. I

at. A. pair of dental pins of unequal length connected together at theirmid-portion by a collar lying at right angles to the axes of the pins.

A pair of pointed dental pins of unequal length characterized by theaxes of the pins being parallel, said pins being connected by a commoncollar in a plane at riglitangles to said axes and by the further proiision'of a plurality ofcement receiving grooves on each of said pins.

GEORGE E, (30X.

